Internal
The threat posed by internal parasites is increasing as worm and fluke populations build resistance to drenches. AWI has developed means of addressing the problem through the better use of existing technologies, as well as the development of new products and new methods to diagnose severity.
Internal parasites and scouring
Background
Better use of existing technologies
New products and practices
New diagnostic tests
Internal parasites (worms and fluke) are estimated to be costing the Australian sheep industry $369m per year. This cost includes mortalities and production losses (reduced wool cut, stained wool, lowered staple strength), as well as the direct costs of control (mainly drenches and labour).
The impact of internal parasites is undoubtedly escalating. The estimated cost in 1995 was $222m. The reason for this blow-out is drench resistance. Resistance by worms to the 'white' and 'clear' drench groups is long established. Resistance to the newest major drench group, the macrocyclic lactones or MLs (the 'mectins'), is now also wide-spread.
It is unlikely that new drenches will be developed in time to solve the resistance problem. Sheep are not a priority for investment by multinational animal health companies and the costs involved in bringing a new compound to market are very high.
AWI is addressing the problems of internal parasites and scouring in three ways:
- Better use of existing technologies
- New products and practices
- New diagnostic tests
Better use of existing technologies
Control of worms, lice and flies can be improved in many sheep flocks by applying principles of integrated parasite management (IPM). IPM means that a range of chemical and non-chemical methods are brought together to tackle the parasite problem.
AWI's flagship project in this area is the Integrated Parasite Management - sheep (IPM-s) project. IPM-s is a $2.6 million investment over the three years to 2007 aiming to develop, apply and test IPM systems across a range of wool production environments. There are 22 IPM-s demonstration farms across Australia. Read the IPM section or contact Charlie de Fegely for further information.
Another key project is the development of the WormBoss package. WormBoss is an encyclopaedia of everything you need to know about managing sheep worms. WormBoss is available in website (http://www.wormboss.com.au/) and CD-ROM formats and is being distributed to producers with the help of key drench resellers Elders, Landmark and CRT.
New products and practices
A range of tools can play a part in the management of worms: oral drenches, capsules, grazing management (such as Smart Grazing), strategic nutrition, and breeding worm-resistant sheep.
AWI is investing in research that may lead to new products and practices for the management of worms. AWI and Meat and Livestock Australia (MLA) are jointly investing $2.2m in a series of projects that aim to better understand the genetic code of worms and the way they interact with their sheep hosts. While any commercial outcome may be ten years away, the research could ultimately deliver new drenches, vaccines, or other new tools to control worms.
AWI's IPM-s project is also investigating the application of a fungus that entraps worm larvae on pasture and hence reduces the worm challenge to grazing sheep.
New diagnostic tests
Sheep producers use faecal worm egg counts (FWEC) to determine the size of worm burden being carried by a flock. FWECs are also used to check the effectiveness of drenches. If it is necessary to know what species of worms are present, a larval differentiation test (a dung sample is incubated and the larvae hatching from the eggs identified) is carried out.
These tests are laborious, quite slow and expensive, and not highly accurate. In collaboration with MLA, AWI is investigating new technologies that could make worm diagnosis quicker and more convenient.
See also: external parasites.
Resources
Contact
Dr Johann Schröder
Project Manager, Animal Health and Welfare
Tel: +61 2 8295 3100
Contact via email
Related websites
www.wormboss.com.au
Publications
Listen online
- WormBoss, Innovation Radio, 17 April 2005 (Windows media file 2Mb)
AWI grower networks
Find out about AWI's community-based network groups in each state.